fix: 修复createSelectorQuery exec()不写回调函数时在支付宝小程序报错

src/platforms/mp-alipay/runtime/api/index.js

@@ -41,8 +41,10 @@ function createExecCallback (execCallback) {
         callback(res[index])
       })
     })
+    if (isFn(execCallback)) {
       execCallback(res)
     }
+  }
 }
 
 function addCallback (callback) {